ctrl-d 没有停止 while(getchar()!=EOF) 循环 [英] ctrl-d didn't stop the while(getchar()!=EOF) loop

问题描述

这是我的代码.我用终端在 ubuntu 中运行它.当我在终端中输入 (a CtrlD) 时，程序并没有停止，而是继续等待我的输入.

Here is my code. I run it in ubuntu with terminal. when I type (a CtrlD) in terminal, the program didn't stop but continued to wait for my input.

CtrlD在unix中不是等于EOF吗?

Isn't CtrlD equal to EOF in unix?

谢谢.

#include<stdio.h>

main() {
    int d;
    while(d=getchar()!=EOF) {
        printf(""getchar()!=EOF" result is %d
", d);
        printf("EOF:%d
", EOF);
    }
        printf(""getchar()!=EOF" result is %d
", d);
}

推荐答案

EOF 不是字符.EOF 是 getchar() 到达输入末尾或遇到某种错误时返回的宏.^D 不是EOF 字符".在 linux 下，当你在一行上按 ^D 时发生的事情是它关闭了流，并且 getchar() 调用到达输入的末尾并返回 EOF宏.如果您在一行中间的某处键入 ^D，则流不会关闭，因此 getchar() 返回它读取的值并且您的循环不会退出.

EOF is not a character. The EOF is a macro that getchar() returns when it reaches the end of input or encounters some kind of error. The ^D is not "an EOF character". What's happening under linux when you hit ^D on a line by itself is that it closes the stream, and the getchar() call reaches the end of input and returns the EOF macro. If you type ^D somewhere in the middle of a line, the stream isn't closed, so getchar() returns values that it read and your loop doesn't exit.

请参阅 C 常见问题的 stdio 部分 以获得更好的描述.

See the stdio section of the C faq for a better description.

另外:

在现代系统上，它不反映存储在文件中的任何实际文件结束字符；这是没有更多可用字符的信号.

On modern systems, it does not reflect any actual end-of-file character stored in a file; it is a signal that no more characters are available.

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